Conventional communication devices are designed to be either contention based or non-contention based. Contention based communication devices implement a listen-before-transmit policy for using a channel for communication. Whereas, non-contention based communication devices are not designed to implement a listen-before-transmit policy for using a channel for communication and are incapable of performing channel sensing. However, certain channels mandate contention based channel access. For example, a license free band such as the 3.65 Giga Hertz (GHz) band in the United States mandates contention based channel access. Therefore, use of such channels is restricted to contention based communication devices as non-contention based communication devices are unable to perform channel sensing.
This problem has often been mitigated by modifying the protocol used by non-contention based communication devices so that they monitor the air-interface for out-of-system energy and suspend the next frame if they detect the out-of-system energy. Such devices are required to perform monitoring for each frame, in case it is required to occupy a channel for longer durations. Moreover, the control over the channel cannot be retained for longer durations in case another device starts transmitting on the channel. Further, these devices monitor the channel during a usable part of the frame. Such an approach drastically impacts bandwidth usage on a channel. Moreover, these devices need to make transitions between various modes of operation, which include monitoring mode and transmitting mode. This further impacts the bandwidth usage on the channel.
Accordingly, there is a need for method and apparatus for operation of a communication device which incorporates channel sensing capability in non-contention based communication devices and also addresses at least some of the shortcomings of past and present techniques of communication between wireless devices.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.